The invention relates to a fuel distributor for supplying fuel to injection valves in an internal combustion engine.
The generation of pressure and the injection of fuel are not typically integrated or connected to one another in fuel distribution systems. Rather, a fuel pump generates pressure continuously. This pressure, which is built up independent of the injection sequence, is continuously or permanently available in the fuel distributor, which functions as an accumulator unit. In addition, the compressed fuel is accumulated in a manifold, and then distributed to the injectors via branch lines, or is otherwise made available to injection valves in a cylinder bank.
Prior art fuel distributors are known from DE 196 07 521 C1, DE 197 53 054 C2, and EP 0 866 221 B1.
DE 197 44 762 A1 describes an injection device for a diesel engine in which the fuel distributor comprises a drawn or rolled pipe. Connecting nipples are welded or soldered to this pipe. Insertion bores for receiving the connecting nipples are added to the fuel distributor. The connecting nipples are placed in the insertion bores prior to welding or soldering.
Moreover, disclosed in EP 0 122 848 is a method for producing a hydraulic connection for a hollow body. For this arrangement, a neck-shaped adapter branch is provided on the hollow body. A connecting line is placed on the adapter branch, and is then fixed in place by deforming the wall of the branch.
Connecting elements embodied as threaded bushings are disclosed in WO 2007/033738 A2 and DE 38 21 827 C2 for connecting branch lines to manifolds of fuel distributors. A sealing seat is produced by mechanical machining of the manifold. These threaded bushings are relatively expensive. In addition, the branch line must be provided with a clinch head or sealing nipple. The end of the branch line and the threaded bushing are generally connected via a union nut, resulting in additional costs. Moreover, assembling the branch line is more complex. In addition, there is also a risk of leaks.
Machining the manifold results in high manufacturing costs. In addition, meeting that the requirements for cleanliness in the fuel area has proved problematic, especially the requirement that none of the waste from machining remains in the manifold.
The connecting elements, either turned and/or milled parts, are also complex and relatively expensive to produce. Moreover, solid thick-walled connecting components combined with comparatively thin-walled manifolds are not an ideal combination for joining, especially for soldering.